1. Field of the Invention
The present invention relates generally to prosthetic feet. More particularly, the present invention relates to resilient, energy-storing prosthetic feet with an elongated forefoot.
2. Related Art
Many individuals have lost a limb for various reasons including war, accident, or disease. In most instances these individuals are not only able to live relatively normal lives, but physically active lives as well. Often times, these individuals are aided in their everyday lives by a prosthetic limb. The objective of prosthesis is to provide an artificial limb that simulates the function and natural feel of the replaced limb.
With respect to prosthetic feet, the development of a functional and natural artificial foot has been limited only by material and imagination. Many designs have attempted to copy the anatomy of the foot or simulate its actions by replacing the bones and muscle with various mechanical components. Other designs have departed radically from mere anatomical copying or mechanical simulation by replacing the entire foot with an energy storage element, such as a spring. As the user steps onto the foot, the user""s weight compresses the spring. As the user moves forward, the user""s weight comes off the foot and the energy stored in the spring is used to propel the user forward.
In addition, the performance of these energy storing feet has been altered in various ways, such as by using multiple springs in various configurations, using bladders or resilient materials disposed between various elements, and using multiple springs that deflect at different intervals of foot deflection to add resistance.
As described above, such energy-storing prosthetic feet typically have either a J-shape or a C-shape configuration or profile with broad, continuous curvatures. The length of a J-shaped foot is limited in the vertical direction by the length of the residual limb of the amputee. Similarly, the length of a C-shaped foot is limited in the vertical direction by the length of the residual limb of the amputee, and in the horizontal direction by the typical size of a natural foot. It will be appreciated that the shape and dimensions of the foot can affect or limit the performance or bending characteristics of the foot.
The continued development of improved prosthetic feet is an ongoing goal. It has been recognized that it would be advantageous to develop a prosthetic foot that maximizes the length of an energy-storing member to provide greater energy storage and release, and improved cushion or spring characteristics.
The invention provides a prosthetic foot device with a discrete, straight ankle section with curved sections on both sides to allow extra length to store and return energy during use, to contribute to extra spring or cushion of the foot, and to improve vertical shock resistance. The foot device can include an attachment member coupled to a limb of an amputee, and an elongated forefoot portion. The forefoot portion can extend 1) rearwardly through an upper attachment section attached to the attachment member, 2) downwardly through an ankle section positioned at an ankle location of a natural foot, and 3) forwardly through an arch section, 4) to a toe section positioned at a toe location of a natural foot. The ankle section can include a discrete, straight section oriented substantially vertically. A first curved section can interconnect the attachment section and the straight section, while a second curved section can interconnect the straight section and the arch section.
In accordance with a more detailed aspect of the present invention, the foot device can further include a lower footplate attached to the upper forefoot portion. The footplate can have a toe section positioned at a toe location of a natural foot, and can extend rearwardly through an arch section to a heel section positioned at a heel location of a natural foot.
In accordance with another more detailed aspect of the present invention, the ankle section of the forefoot portion can be positioned at a rearmost location of the foot device, and over the heel section of the lower footplate. Thus, the forefoot portion can be further elongated to store and return energy during use, to contribute to extra spring or cushion of the foot, and to improve vertical shock resistance.
In accordance with another more detailed aspect of the present invention, the foot device can further include an elongated heel portion attached to the upper forefoot portion. The heel portion can have an attachment section attached to the upper forefoot portion, and can extend rearwardly to a heel section positioned at a heel location of a natural foot.
In accordance with another more detailed aspect of the present invention, the forefoot portion, the footplate, and/or heel portion can be flexible to store energy and resilient to return energy. The forefoot portion, the footplate, and/or heel portion can include a composite material with fiber in a resin matrix.
In accordance with another more detailed aspect of the present invention, the forefoot portion, the footplate, and/or heel portion can include at least two laterally separated and adjacent portions.
In accordance with another more detailed aspect of the present invention, the foot device can have an oblique attachment. The attachment member can have a lower oblique surface. The attachment section can have an upper oblique attachment surface attached to the lower oblique surface of the attachment member.
Additional features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention.